This invention relates to producing visual images.
The production, from a continuous parallax view of multiview image, of integral or panoramogramic images for viewing using a decoding screen as 3-D pictures is well-known. A photographic image can be reproduced photographically to provide multiple such images. The need, as hitherto perceived, to reproduce the images photographically has imposed restrictions on the use of such images.
The present invention provides a method by which such images may be reproduced which removes such restrictions.
The invention comprises a method for reproducing an integral or panoraragramic image for viewing using a decoding screen as a 3-D picture comprising printing the image using a high resolution ink printing technique.
Hitherto it has been thoughtxe2x80x94generally speaking quite correctlyxe2x80x94that printing by any of the conventional printing techniques would lose so much of the parallax information in an integral or panoramagramic image that the image, even when viewed using a decoding screen, would be poor and not recognisably 3-D. It is now found, however, that high resolution printing techniques preserve the parallax information so as to give very, good 3-D pictures.
The printing technique may be a relief printing technique such as gravure printing and may be a frequency modulated technique, in which the dots are not regularly spaced but spaced more or less closely according to the print density required, or an amplitude modulated technique in which the dots are regularly spaced but vary in size.
The printing technique may be a half tone printing technique, and may be a screen printing technique.
For off-the-page viewing, a resolution of 40 screen lines/cm or higher is found to give very good results. Parallax information can be retained at greater screen pitches. The screen pitch will depend also on the lenticular/microlens pitch that produced the original image. An integral number of addressable points may be located behind each microlens, but it is not essential.
The printing technique may be a colour printing technique.
The invention also comprises a print produced by a method according to the invention, as well as such a print in combination with a decoding screen. The decoding screen may be attached to the print, and may be applied to the print by an embossing technique.
The image points may, however, comprise pixels on an active image screen such as an lcd or crt screen or any other electronically addressed display system.
Surprisingly, the resolution of the image may be less than 400 dots or pixels per cm, and may be as low as 32 dots or pixels per cm. Put another way, the resolution of the image may be of the order of 1,000 dots or pixels per square cm, good results being obtained with a resolution between 2,000-5,000 dots per square cm. The figure is related to the decoding screen pitch. The figure of 32 dots or pixels per cm is suitable for 0.6 mm pitch microlenses.
The image point spacingxe2x80x94the dot or pixel spacingxe2x80x94may be more than half that of the decoding screen lens spacingxe2x80x94this is also surprising, as it means there can be less than two pixels per microlens.
The image points may comprise a computer generated amplitude distribution, which may be generated ab initio by computer software, or it might be generated by computer software manipulation of three dimensional information derived from imaging a real scene. Whilst this can clearly be photographic imaging, the real scene is not necessarily imaged in visible radiation but may be imaged by radar, for example, or x-rays, magnetic resonance, ultrasound or any other imaging technique capable of providing three-dimensional image data whether in a single take or tomographically.
Two or more amplitude distributions generated by the same or by different meansxe2x80x94e.g. one photographically, one by computer software, may be sectionalised and/or manipulated and mixed in spatial form.
The displayed images may be a still or a moving imagexe2x80x94a moving image may be mixed with a still image.
The invention also comprises apparatus for producing an integral panoramagramic image comprising an image represented as an array of image points with a density corresponding to high resolution ink printing and a decoding screen.
The array of image points may be comprised in a pixel screen, and the apparatus may comprise an input to the pixel screen of a computer generated amplitude distribution comprising three dimensional image information.
The decoding screen may be cylindrical-lenticular or integral microlens. Other forms of decoding screen may be used, however, such as a parallax barrier, a two dimensional pinhole array or even a scanning slit. If the amplitude distribution is computer generated, or computer manipulated, there will be no need to limit the decoding arrangement to match the image taking arrangement.
The invention also comprises a full spatial image capturing arrangement comprising:
a multiple-imaging objective lens system, having an imaging zone of extended depth corresponding to an object region of extended depth;
a lensed encoding screen located in said imaging zone forming an encoded image from the imaging zone;
a copy lens arrangement transferring the encoded image to an image plane; and
an image recording device for the image in the image plane.
Multiple-imaging is not to be confused with xe2x80x9cmultiviewxe2x80x9d, a term used to describe multiple separate images taken from spaced apart lenses for eventual assembly into a composite image which gives an impression of three dimensions in the image, but which is by no means full spatial imaging with continuous parallax. xe2x80x9cMulti-imagingxe2x80x9d here refers to a synthesised aperturexe2x80x94a wide aperture lens simulated by an assembly of smaller lenses.
Such an arrangement can be used to capture images to be reproduced or displayed using methods and apparatus as above described.
The multiple-imaging objective lens system may comprise a double transmission screen and a convex lens. The double transmission screen may comprise a double cylindrical lenticular transmission screen or a double integral microlens screen.
The multiple-imaging objective lens system may, however, comprise a segmented convex lens.
The lensed encoding screen may comprise a cylindrical lenticular screen or an integral microlens screen.
The image recording arrangement may comprise a photographic emulsion (where reproduction is intended to be e.g. by printing, especially) or a charge coupled device array or other electronically addressable array of sensitive elements.